Wittichenite, Cu3BiS3
Wittichenite (bluish grey), chalcopyrite (yellow needles),
covellite (blue) in bornite from LÃ¥ngban, Sweden.
Size 0.3 mm. Reflected
light, open nicols. The white mineral in the picture is native bismuth.
Photo © Kjell Gatedal, School of Mines and Metallurgy, Filipstad, Sweden